In commercial business situations, security systems are commonly employed to monitor and protect property, as schematically shown in FIG. 1. Various threats may be of interest, and these threats may be either natural or human-related. Natural threats would include such conditions as the presence of fire, excess water where it is not desired, over-temperature alarms in refrigeration equipment, under-temperature alarms, and such. Human-related threats would include such conditions as unauthorized entry to a given area, removal of equipment from a specified area, nuclear, biological, or chemical attack; and the like. Security systems typically employ sensors to detect a condition related to the threat. For example, to detect the presence of a fire, a fire alarm sensor would be installed in the specified area to detect an elevated temperature condition. The sensor, upon detecting the heat from fire, would send an alert indication to a central facility, typically a computer system, which would record the detected condition as an event.
When the event is recorded, then it must be evaluated to determine what appropriate action to take place. Occasionally the event is ignored, as for example, when a door having a sensor is opened during normal business hours. After hours, however, the computer system may generate an alarm. Other events, such as an over-temperature alert indicating a fire, may always generate an alarm. The alarm may be some physical manifestation such as a rotating light, an audible sound, or both. The alarm may also be a notification of the event sent to an interested recipient so that the recipient can take some action. The physical manifestation may itself serve as notification. Typically, however, the recipient may receive notification by some telephonic means such as telephone (via dedicated line or switched network), pager, cellular phone, or radio.
Many different types and configurations of security systems have been proposed to deal with this process. U.S. Pat. No. 5,278,539, issued Jan. 11, 1994, to Lauterbach et al., describes an emergency alerting system in which an alarm is transmitted to an automated controller for a radio transmitter. The transmitter may be part of an existing radio paging system. The receiving unit transmits an acknowledgment back to the sending unit.
U.S. Pat. No. 4,956,875, issued Sep. 11, 1990, to Bernard et al., discloses an FM transmitter having first and second encoding means, the first encoding means which enables the selection of all receivers in a given location, and the second encoding means which enables a broadcast to particular receivers in the selected location. The FM receivers are receptive but inactive until the encoded signal specific to that receiver is received; the fully activated receiver then sounds an audible alarm to alert and notify persons in the vicinity.
U.S. Pat. No. 6,288,644, issued Sep. 11, 2001, to Matthews et al., discloses a perimeter alarm sensing means for detecting intrusion into the secure space and peripherally discusses transmission of an alarm to a recipient. The system includes a first and a second mounting apparatus, a reflector assembly, a monitor, a receiver, and an alarm for a timing device.
U.S. Pat. No. 6,049,272, issued Apr. 11, 2000, to Lee et al., discloses an automated data transmission system for sending alarms directly to law enforcement or security personnel. The system uses various means of communications, including phone line, pager, and wireless transmitters. The choice of communications channel is made at the telephone company and not necessarily at the host security computer.
Security system configurations are complicated by the need to classify the events on the basis of need-to-know, to send alarms and notifications only to those recipients that are have an interest in the alert condition generating the alarm, and to facilitate interaction between the security facility and the alarm recipient. Concerning classification of events based on a need-to-know, different alarms are of interest to different recipients or groups of recipients. For example, a fire alarm condition would be of interest to the fire station and to the owner of the business from which the fire alarm originated, but not to every worker employed by the business. An unauthorized open door alarm would be of interest to law enforcement personnel and to the owners of the business, but not to fire department personnel. Conditions in one building of a multi-building complex would be of interest only to the security personnel having responsibility for that building, and then only to those on duty at the time of the occurrence of the condition, but not to security personnel assigned to adjacent buildings.
Once the alert is detected, evaluated, and the appropriate recipients identified, then some means must be employed to send notification of the alert to just those recipients having an interest in the particular threat condition and not to others, so as not to overburden all personnel by requiring them to differentiate between alerts of interest and those which are of no interest. It would be desirable to partition the recipients into groups based upon different criteria, i.e. association with the particular alarm, the type of alarm (e.g. fire, open door, particular building, etc.), or an organizational unit.
When the recipient receives the notification, then there should be some interactive mechanism to allow the recipient to respond. The central facility generating the notification should know that the appropriate recipient received the alarm notification, so there must be a means for the recipient to acknowledge its receipt. Furthermore, the central facility should be sure that the recipient responding to the alarm is authorized to act, so that there should be some kind of authentication capability which allows the recipient to identify himself. Finally, if the recipient fails to respond, the central facility should have the means of identifying an alternate recipient, sending the notification to the alternate recipient, and logging the fact that the original recipient did not respond, in order to support further investigation by the managers, if necessary.
As with any complicated system, equipment may malfunction. In a security system, it is desirable to determine whether the failure of a recipient to respond to a notification is due to the fact that the recipient is unavailable or that the recipient did not receive the notification because of equipment failure. Such information would allow the security system to self-generate an alarm for its own equipment failure and to summon maintenance personnel to deal with the outage.
It can therefore be seen that there is a need for a security system that can receive numerous alerts associated with the security of a facility, evaluate the alerts to determine which alerts require attention, generate alarms and notifications, determine group of recipients who are authorized to deal with the alert, determine what message to send to the group of recipients, send the message by wireless radio signal, and record acknowledgments from the recipients. Such a security system should also be able to perform self-tests to determine if critical parts of the system are operational and, if not, summon maintenance personnel for correction.